Notes 4. Carbon and its Compounds - Functional Group and Nomenclature of Hydrocarbons | Class 10 Science - Toppers Study

Chapter 4. Carbon And Its Compounds

Functional Group: 

Functional group is a group of an atom or atoms in any carbonic compound which are bonded each other in special manner. That is generally region of chemical reactivity in carbonic atoms.

Oxygen, chlorine, sulpher, nitrogen and other elements can be presence as a part of a functional group in carbonic compounds. 

Hetroatoms: The element which replaces hydrogen in a compound is called hetroatom. 

Example: Oxygen, chlorine, sulpher, nitrogen and other elements can be presence as a part of a functional group in carbonic compounds, such elements are called hetroatoms.

Some List of Functional Groups: 

(i) Halogen: Halogens are non-metal elements like fluorine, chlorine, bromine and Iodine etc situated in modern periodic table in group 17. 

(ii) Alcohol: Alcohol is another function group which joining to a series of hydrocarbon forms the group of atoms 

Example: - OH

(-OH) joins to hydrocarbon like alkane form various type of alcohols, such methanol, ethanol and propanol etc.  

(iii) Aldehyde: It is a functional group in which carbon atom linked with a single oxygen atom in double bond along with one hydrogen atom. 

(iv) Ketone: Ketone is also a functional group which joins to hydrocarbons form a series of molecules. In ketone carbon atom linked with a single oxygen atom in double bond. 

(v) Carboxylic acid: It is also a functional group, in which a carbon atom is  linked with oxygen atom in double bond and also linked with hydroxide.

Homologous Series: 

A series of compounds in which the same functional group substitutes for hydrogen in a carbon chain is called a homologous series.

Examples: 

Increasing in molecular Mass in Homologous series: 

As the molecular mass increases in any homologous series, a gradation in physical properties is seen. This is because the melting points and boiling points increase with increasing molecular mass. Other physical properties such as solubility in a particular solvent also show a similar gradation. But the chemical properties, which are determined solely by the functional group, remain similar in a homologous series.

Nomenclature of carbon Compounds: 

Naming of organic compound systematically called as nomenclature. 

IUPAC Name: 

Name formed by this nomenclature is called IUPAC name of molecules.

Nomenclature of Hydrocarbons:

According to presence of carbon atoms in hydrocarbon molecules naming of molecules are as follows: 

We have already known that Hydrocarbons are three types and their nomenclature are as follows:

(i) Alkane (Single bond):

Functional Group Halogen and its nomenclature:

For -(Cl) "chloro" is used, (-Br) "Bromo" is used and (-I) "Iodo" is used. 

(A) Alkane with Chlorine

(B) Alkane with Bromine

(C) Alkane with Iodine

Functional Group Alcohol and its nomenclature:

 To give the name to Alcohol group we use a "suffix" -"ol" With the name of simple Alkane

(D)Alcohol

Note: Above Examples (A), (B), (C) and (D) are also Homologous series: 

(ii) Alkene (Double bond)

(iii) Alkyne (Triple bond)